Currently test_plugin_position.xhtml skips Windows. It should test Windows. However, pluginGetEdge doesn't work right on Windows, it doesn't return coordinates relative to the window frame.

Comment on attachment 385956 [details] [diff] [review] Part 2: compute accurate clip region nptest_platform.h comments need an update. but other than that this looks to be working correctly. I'm curious about how this test works. In test_plugin_position.xhtml it looks like you're creating an hbox that falls under the plugin, so the dimensions and clipping should be equal?

The hbox is just a trick I'm using to determine whether 1 CSS pixel equals 1 screen pixel, and to figure out what the top-left of the document's viewport is relative to the top-left of the window frame decorations. It doesn't affect the plugin at all.

(In reply to comment #2) > (From update of attachment 385956 [details] [diff] [review]) > nptest_platform.h comments need an update. What do you mean?

http://hg.mozilla.org/mozilla-central/rev/e58ae7ce8805 http://hg.mozilla.org/mozilla-central/rev/557fbc25bab3